The founder of pub chain JD Wetherspoon (JDW.L) has said Boris Johnson should not break the law in pursuit of a no deal Brexit, but urged the prime minister to do everything he can to get Britain out of the customs union.

Tim Martin, one of the most prominent Brexit-supporting figures in business, told Yahoo Finance UK: “Do I feel that Boris should break the law? I think he shouldn’t break the law, he should obey the law, but he should try and leave.

Westminster has been full of speculation that Johnson is set to defy a law passed by rebel MPs at the start of the month. The law forces the prime minister to write to the EU asking for an extension to the Brexit timetable if a deal is not reached by 19 October.

Martin, who founded JD Wetherspoon in 1979 and chairs the company, said it was “a difficult question” when asked whether he supported Johnson breaking the law.

“The leaflet that was sent through the door of everyone in the country said: this is a once in a generation decision, you decide, the government will implement your decision,” Martin said. “They [MPs] don’t want to do it. They’ve constructed this argument that people didn’t vote for no deal.”

Martin campaigned for Britain to leave the EU ahead of the 2016 referendum and has consistently called for Brexit to be enacted since. He is one of the most prominent Brexit-supporting business people in the UK. JD Wetherspoon operates almost 900 pubs across the UK, with sales of £1.8bn last year.

“It’s perfectly legitimate if you’re planning in a business to try and plan for the downside,” he said. “I think it’s a sensible approach generally to say, well what happens if all these things go wrong? But it’s not a prediction of what actually is going to happen.”

Wetherspoon chairman Tim Martin speaks during a rally of the Brexit Party in Peterborough on 7 May. Photo: Simon Dawson/Reuters

Martin argued that no deal would actually boost the UK economy, if the government decided to abandon all tariffs on imports. He said goods like rice, oranges. bananas, and Australian wine could see lower prices.

Martin denied that the fall in the pound since the 2016 would offset any gains made from abandoning tariffs.

‘We need immigration’

Martin called for a “liberal approach” to immigration post-Brexit and said: “We need immigration in the UK. There’s a relatively low birth rate.”

“When you look at the New Zealand, Australia, North America, they’ve had higher immigration rates than we have and they’ve done very well,” Martin said. “I just think it should be controlled by our government, not controlled by people we haven’t elected. I think the EU’s given immigration a bad name.”

The pub boss said there would be “dancing in the streets, breakdancing in our pubs” if Britain leave the UK on 31 October.

Martin was speaking to the press after his pub group reported its preliminary results for the 12 months to the end of July. JD Wetherspoon’s sales rose by 6.8% put profit dipped by 4.5%.